the fusion of distichous branches. It 
does not prove that the ear of maize 
did actually arise in this way, although 
it would undoubtedly have been re- 
garded as proof by earlier proponents 
of the fusion hypothesis. 
Also during the summer of 1944 
my attention was called to some pecu- 
liarities of Tripsacum dactyloides (1. ) 
L. by Dr. Leon Croizat who suggested 
that they seem to have a bearing on 
the question of fusion. In this spe- 
cies the inner surfaces of the several 
branches of the terminal inflorescences 
are so sculptured that the irregularities 
of one branch are reciprocal to those 
of the adjoining branch. Because of 
this the branches, when brought to- 
gether, form a cylinder which bears 
spikelets on its circumference ; a struc- 
ture comparable to an ear of maize. I 
do not regard this condition as evi- 
dence for fusion as it is obviously noth- 
ing more than the result of the consid- 
erable compression to which the inflo- 
rescence is subjected while still in the 
sheath. The same condition in less 
conspicuous form is regularly encoun- 
tered in maize tassels where the lateral 
Figure 1. A case of fusion of two of the lat- 
eral branches of a maize tassel. The two-ranked 
branches are joined for slightly more than 
half of their length, but separated for the re- 
mainder. 
[ 47 ] 
